Drug delivery systems and related methods

ABSTRACT

Systems and methods for isolating and/or desiccating a portion of a drug delivery tract of a drug delivery apparatus to reduce water vapor content therein are provided. For example, there is provided a metered dose inhaler for delivering aerosolized medicament or other matter to a user. The aerosolized medicament or other matter may be discharged from a discharge passageway within the inhaler into an inhalation passageway for inhalation by a user, and the inhaler may comprise a seal member operative to selectively isolate the discharge passageway from the inhalation passageway and external environment during inactivity. The inhaler may further comprise a desiccant material arranged to withdraw moisture from the isolated discharge passageway. In other instances, desiccant material may be arranged to withdraw moisture from the discharge passageway of the inhaler without isolating the discharge passage during inactivity.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/754,585, filed Apr. 8, 2020, which is a national stage ofinternational application No. PCT/US2018/054721, filed Oct. 5, 2018,which claims the benefit of U.S. Provisional Patent Application No.62/569,901, filed Oct. 9, 2017, and U.S. Provisional Patent ApplicationNo. 62/639,911, filed Mar. 7, 2018, the contents of which are herebyincorporated by reference in their entirety.

BACKGROUND Technical Field

This disclosure generally relates to drug delivery systems and relatedmethods, and, more particularly, to drug delivery systems and methodsfor isolating and/or desiccating a portion of a drug delivery tract of adrug delivery apparatus to reduce water vapor content therein. Examplesinclude aerosol delivery units suitable for delivering a dose ofaerosolized matter for inhalation by a user while preventing orminimizing the deposition of matter (e.g., buildup of hygroscopic drugproduct) within a discharge passageway thereof, or from otherdetrimental effects arising from moisture infiltration into the aerosoldelivery unit.

Description of the Related Art

It is well known to treat patients with medicaments contained in anaerosol, for example, in the treatment of respiratory disorders. It isalso known to use for such treatment, medicaments which are contained inan aerosol and are administered to a patient by means of an inhalationdevice comprising a mouthpiece and a housing in which an aerosolcanister is loaded. Such inhalation devices are generally referred to asmetered dose inhalers (MDIs). The aerosol canisters used in suchinhalation devices are designed to deliver a predetermined dose ofmedicament upon each actuation by means of an outlet valve member (e.g.,metering slide valve) at one end which can be opened either bydepressing the valve member while the canister is held stationary or bydepressing the canister while the valve member is held stationary. Inthe use of such devices, the aerosol canister is placed in the housingwith the outlet valve member of the canister communicating with themouthpiece. When used for dispensing medicaments, for example, inbronchodilation therapy, the patient holds the housing in a more or lessupright position and the mouthpiece of the inhalation device is placedin the mouth of the patient. The aerosol canister is then actuated todispense a dose of medicament from the canister which is then inhaled bythe patient. The effective delivery of medicament to the patient usingan inhalation device such as a conventional MDI may be hindered by thedeposition and accumulation of the discharged medicament or other matterwithin the discharge passageway (e.g., buildup of hygroscopic drugproduct in the valve stem), or from other detrimental effects arisingfrom moisture infiltration into the device. The same or similar effectsmay arise in the drug delivery tract of other drug delivery apparatuses,such as, for example, dry powder inhalers (DPIs) and drug injectors.

BRIEF SUMMARY

Embodiments described herein provide systems and methods for isolatingand/or desiccating a portion of a drug delivery tract of a drug deliveryapparatus to reduce water vapor content therein. This includes, forexample, aerosol delivery systems and related methods particularly wellsuited for delivering a dose of aerosolized matter in an efficient andreliable manner for inhalation by a user while preventing or minimizingthe deposition of matter within a discharge passageway thereof, orotherwise minimizing or eliminating other detrimental effects that mayarise from moisture infiltration into the system. Embodiments include,for example, aerosol delivery systems featuring devices and techniquesfor selectively sealing at least a portion of the discharge passagewaywhen the aerosol delivery system is not being used to discharge themedicament and/or for exposing the discharge passageway to a desiccantmaterial to remove moisture therefrom. It has been found that sealingthe discharge passageway and removing moisture therefrom can, inconnection with at least some products, substantially eliminate orsignificantly reduce the deposition or accumulation of matter within thedischarge passageway which may otherwise hinder consistent delivery(e.g., consistent shot weight) of the discharged medicament or otheraerosolized matter. Embodiments of the aerosol delivery systems withonboard desiccant material may advantageously eliminate the need fortraditional desiccant materials that are often provided within productpackaging for moisture control purposes. In addition, in some instances,embodiments may sufficiently minimize detrimental effects associatedwith moisture exposure and eliminate the need for foil overwrap or othertechniques used to enhance product shelf life. Still further, benefitsof the moisture management techniques disclosed herein may extendmoisture protection beyond initial product storage to provide moisturecontrol functionality throughout usable product life.

In addition, inhaler embodiments disclosed herein featuring devices andtechniques for selectively sealing at least a portion of the dischargepassageway may enable unsealing and sealing of the discharge passagewaywith minimal impact on the actuation force or canister return force.Moreover, inhaler embodiments may allow for unsealing and sealing of thedischarge passageway in timed coordination with the discharge ofaerosolized matter so as to not impact or hinder the flow path of suchmatter. In this way, benefits of the embodiments disclosed herein may berealized without appreciably or unduly hindering the operation andeffectiveness of the aerosol delivery systems. Disclosed embodiments mayalso operate similar to inhaler devices lacking such features orfunctionality for selectively sealing the discharge passageway and/orexposing the same to a desiccant material such that users may be unawareof the additional features and functionality during use.

The drug delivery systems described herein, in certain embodiments, aresuited to delivery of aerosol formulations that include one or moisturesensitive components or exhibit a high solids content. For example,moisture sensitive components include any material that, when exposed toambient moisture or condensation events such as those associated withaerosolization of a medicament delivered from a metered dose inhaler,may absorb or adsorb water in a manner that leads to increaseddeposition of the material within the discharge passageway of an aerosoldelivery system.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a conventional canister of an MDIshowing an outlet valve member thereof, which includes a movable valvestem extending from a canister body thereof, the valve stem defining aportion of a discharge passageway extending from the canister body to adischarge orifice provided within the MDI.

FIG. 2A is a CT scan of a discharge passageway of a conventional MDI,showing the deposition or accumulation of matter therein arising fromrepeated use of the device.

FIG. 2B is a CT scan of a discharge passageway of an MDI according tocertain aspects and techniques of the present invention, showing thedischarge passageway substantially free of deposited or accumulatedmatter despite repeated use of the MDI to dispense medicament.

FIG. 3 is an isometric view of an aerosol delivery unit, according toone example embodiment.

FIG. 3A is a side view of the aerosol delivery unit of FIG. 3 with aportion thereof in cross-section, showing the unit in a standby orstorage configuration in which the discharge passageway is sealed fromthe external environment and also exposed to a desiccant material.

FIG. 3B is a side view of the aerosol delivery unit of FIG. 3 with aportion thereof illustrated in cross-section, showing the unit in adischarge configuration in which the discharge passageway is unsealed toenable aerosolized matter to be discharged from the canister into aninhalation passageway for delivery to a user.

FIG. 3C is an isometric view of some components of the aerosol deliveryunit of FIG. 3 shown in collapsed and exploded configurations.

FIG. 3D includes isometric views showing components of a cartridge ofthe aerosol delivery unit of FIG. 3, which includes a desiccant housingattached to the end of an aerosol canister with a desiccant materialreceived therein.

FIG. 4 is a partial cross-sectional side view of an aerosol deliveryunit, according to another example embodiment, showing the unit in adischarge configuration in which the discharge passageway is unsealed toenable aerosolized matter to be discharged from the canister into aninhalation passageway for delivery to a user.

FIG. 5 is an exploded isometric view of a portion of an aerosol deliveryunit, according to another example embodiment.

FIG. 6 is a collapsed isometric view of the portion of the aerosoldelivery unit of FIG. 5, showing a seal member thereof in a closedposition over a discharge orifice through which aerosolized matter isdischarged during use.

FIG. 7 is a cross-sectional side view of the portion of the aerosoldelivery unit shown in FIGS. 5 and 6, showing the seal member in an openposition in which an aerosol discharge path through the dischargeorifice is not obstructed by the seal member.

FIG. 8 is a skewed isometric view of a portion of an aerosol deliveryunit, according to yet another example embodiment, in which a sealmember thereof is in an open position.

FIG. 9A is a cross-sectional side view of the portion of the aerosoldelivery unit of FIG. 8 with the seal member in a closed position.

FIG. 9B is a cross-sectional side view of the portion of the aerosoldelivery unit of FIG. 8 with the seal member in the open position.

FIG. 10 provides schematic diagrams of various seal member arrangementsthat may be used to selectively isolate a discharge passageway of anaerosol delivery unit.

FIG. 11 shows another example embodiment of an aerosol delivery unithaving a movable ball seal and a separate desiccant housing.

FIG. 12 shows another example embodiment of an aerosol delivery unithaving a movable gate element to selectively close off a desiccantchamber thereof.

FIG. 13 shows another example embodiment of an aerosol delivery unithaving a desiccant chamber formed integrally with a housing thereof, andincluding a manipulable mouthpiece cap that is configured to controlmovement of a seal member for selectively isolating a dischargepassageway of the unit.

FIG. 14 shows a supplemental seal member that is used to block anaperture in the side of the valve stem of a conventional canister of anMDI when the valve stem is in an expanded or uncompressed position.

FIG. 15 is an isometric cross-sectional view of a portion of an aerosoldelivery unit, according to another embodiment, which includes amouthpiece cap having a desiccant chamber therein and a seal member forselectively isolating a discharge passageway of the aerosol deliveryunit from the external environment.

FIG. 16 is a schematic diagram of an alternate arrangement of amouthpiece cap having a desiccant chamber therein and a seal member forselectively isolating a discharge passageway of the aerosol deliveryunit from the external environment.

FIG. 17 is a partial cross-sectional side view of an aerosol deliveryunit, according to another example embodiment, showing the unit in astandby or storage configuration in which the discharge passageway issealed from the external environment and also exposed to a desiccantmaterial.

FIG. 18 is a top perspective view of a portion of the aerosol deliveryunit of FIG. 17 showing additional details of a biasing element, in theform of a resilient band, for assisting in sealing the dischargepassageway, along with depicting alternate band geometry.

FIG. 19 is an isometric view of an aerosol delivery unit, according toyet another example embodiment.

FIG. 20 is an exploded isometric view of the aerosol delivery unit ofFIG. 19.

FIG. 21A is a side view of the aerosol delivery unit of FIG. 19 with aportion thereof illustrated in cross-section, showing the unit in astandby or storage configuration in which the discharge passageway isexposed to a desiccant material.

FIG. 21B is a side view of the aerosol delivery unit of FIG. 19 with aportion thereof illustrated in cross-section, showing the unit in adischarge configuration in which the discharge passageway is temporarilyisolated from the desiccant material as aerosolized matter is dischargedfrom the canister into an inhalation passageway for delivery to a user.

DETAILED DESCRIPTION

In the following description, certain specific details are set forth inorder to provide a thorough understanding of various disclosedembodiments. However, one of ordinary skill in the relevant art willrecognize that embodiments may be practiced without one or more of thesespecific details. In other instances, well-known structures and devicesassociated with MDIs or other drug delivery devices or components maynot be shown or described in detail to avoid unnecessarily obscuringdescriptions of the embodiments.

Unless the context requires otherwise, throughout the specification andclaims which follow, the word “comprise” and variations thereof, suchas, “comprises” and “comprising” are to be construed in an open,inclusive sense, that is as “including, but not limited to.”

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure or characteristicdescribed in connection with the embodiment is included in at least oneembodiment. Thus, the appearances of the phrases “in one embodiment” or“in an embodiment” in various places throughout this specification arenot necessarily all referring to the same embodiment. Furthermore, theparticular features, structures, or characteristics may be combined inany suitable manner in one or more embodiments.

As used in this specification and the appended claims, the singularforms “a,” “an,” and “the” include plural referents unless the contentclearly dictates otherwise. It should also be noted that the term “or”is generally employed in its sense including “and/or” unless the contentclearly dictates otherwise.

Embodiments described herein provide systems and methods for isolatingand/or desiccating a portion of a drug delivery tract of a drug deliveryapparatus to reduce water vapor content therein. This includes, forexample, aerosol delivery systems and related methods particularly wellsuited for delivering a dose of aerosolized matter in an efficient andreliable manner for inhalation by a user while preventing or minimizingthe deposition of matter within a discharge passageway of the deliveryunit throughout repeated use thereof. Embodiments include, for example,aerosol delivery systems comprising a seal member to selectively sealoff at least a portion of a discharge passageway of the device when notactively discharging aerosolized matter therethrough. Embodiments of thedelivery systems may further include a desiccant material in fluidcommunication with the discharge passageway to assist in withdrawingmoisture therefrom. Advantageously, the systems and methods describedherein may assist in ensuring consistent delivery of the aerosolizedmatter (e.g., consistent shot weight) which may otherwise be compromisedby fouling of the discharge passageway. Other advantages will beappreciated from a detailed review of the present disclosure.

Although the drug delivery systems described herein are shown anddescribed largely in the context of metered dose inhalers (MDIs) fordelivering medicament or other aerosolized matter to a user, it will beappreciated by those of ordinary skill in the relevant art that featuresand aspects of such systems may applied to other devices and for otherpurposes, including other drug delivery apparatuses having one or moredrug delivery tracts.

By way of background, FIG. 1 shows a cross-sectional view of aconventional canister 10 of an MDI showing an outlet valve member 12thereof, which includes a movable valve stem 14 extending from acanister body 16 that contains the matter to be discharged. The valvestem 14 defines a portion of a discharge passageway 20 extending fromthe canister body 16 to a discharge orifice 22 provided within the MDI.As will be appreciated by those of ordinary skill in the relevant art,when the valve stem 14 is displaced relative to the canister body 16, ametered dose of the matter contained with the canister body 16 isdischarged through the discharge orifice 22 after passing through thedischarge passageway 20. More particularly, and according to theparticular arrangement shown in FIG. 1, matter contained within thecanister body 16 enters the valve stem 14 through an aperture 24 in aside thereof after the valve stem 14 is sufficiently displaced relativeto the canister body 16, and then travels through the valve stem 14toward the discharge orifice 22 within the MDI to be dispersed into aninhalation passageway to be inhaled by a user through a mouthpieceaperture. The discharge passageway 20 and inhalation passageway of theinhaler, which extends from an outlet of the outlet valve member 12 tothe mouthpiece aperture, may be referred as a drug delivery tract.

With continued reference to FIG. 1, and in accordance with conventionalMDI devices, the discharge passageway 20 leading from the canister body16 to the discharge orifice 22 generally remains open and exposed to theenvironment external to the MDI device, such as through the dischargeorifice 22 and/or the aperture 24 in the side of the valve stem 14. Inthis manner, the discharge passageway 20 is susceptible to moistureingress which can lead to accelerated fouling of the dischargepassageway 20, namely, the deposition or accumulation of matter withinthe discharge passageway 20.

Embodiments disclosed herein are provided to limit or substantiallyeliminate the deposition or accumulation of matter within a dischargepassageway of a metered dose inhaler or other drug delivery device by(i) selectively sealing the discharge passageway when not activelydischarging matter therethrough, and/or (ii) exposing the dischargepassageway to a desiccant material.

By way of example, FIG. 2A provides a CT scan showing the accumulationof matter within a discharge passageway of a conventional MDIarrangement arising from repeated use thereof, and FIG. 2B provides a CTscan of a comparable discharge passageway provided in connection withfeatures and techniques described herein to limit or substantiallyeliminate the deposition or accumulation of matter within the dischargepassageway. The respective devices shown in FIGS. 2A and 2B wereoperated under similar environmental conditions (e.g., temperature andrelative humidity) and under similar operational parameters to provide asuitable comparison between a conventional MDI (FIG. 2A) and a deviceconstructed in accordance with aspects and techniques disclosed herein(FIG. 2B). As can be appreciated from a review of FIGS. 2A and 2B, thedevice constructed in accordance with aspects and techniques disclosedherein shows significant improvement in preventing the deposition oraccumulation of matter within the discharge passageway, whichadvantageously helps to ensure the consistent delivery of a desired doseof the aerosolized matter (e.g., consistent shot weight).

FIGS. 3, 3A and 3B show one example embodiment of an aerosol deliveryunit 100 for selectively delivering a dose of aerosolized matter(referred to generally as a metered dose inhaler or MDI), and FIGS. 3Cand 3D show additional details of some of the components thereof.

The aerosol delivery unit 100 includes a base housing 104 and a canister110 received in the base housing 104, the canister 110 beingdisplaceable from an initial position I, as shown in FIG. 3A, to adischarge position D, as shown in FIG. 3B, for selectively discharging adose of aerosolized matter for inhalation by a user. The canister 110comprises a canister body 116, which contains the matter to bedischarged, and an outlet valve member 112, which includes a movablevalve stem 114 that extends from the canister body 116. The valve stem114 defines a portion of a discharge passageway 120 extending from thecanister body 116 to a discharge orifice 122 provided within the aerosoldelivery unit 100, which in turn leads to an inhalation passageway 126through which the aerosolized matter passes before being dischargedthrough a mouthpiece aperture 128 for inhalation by the user during aninhalation event. The discharge passageway 120 and the inhalationpassageway 126 may be collectively referred to as a drug delivery tract.As will be appreciated by those of ordinary skill in the relevant art,when the valve stem 114 is displaced relative to the canister body 116,as shown in FIG. 3B, a metered dose of the matter contained with thecanister body 116 will be discharged through the discharge orifice 122for inhalation by a user via the inhalation passageway 126.

With reference to FIG. 3, the aerosol delivery unit 100 may furtherinclude a dose counter assembly 107 secured to an upper under of thecanister 110 to provide dose counting functionality and to provide auser interface for depressing the canister 110. The aerosol deliveryunit 100 may also include a cap 105 to cover the mouthpiece aperture 128of the aerosol delivery unit 100 when storing the unit 100. The cap 105may be completely separable from the base housing 104, or may be coupledto the base housing 104 by a tether 106, which enables the cover 105 tobe removed from the mouthpiece aperture 128 while still remainingcoupled to the base housing 104.

With reference to FIGS. 3A and 3B, the aerosol delivery unit 100 furtherincludes a seal member 130 movable between a closed position C (FIG.3A), in which the seal member 130 covers a discharge outlet of thedischarge passageway 120, namely, discharge orifice 122, in order toisolate the discharge passageway 120 from the inhalation passageway 126,and an open position O (FIG. 3B), in which the discharge outlet, namely,discharge orifice 122, is in fluid communication with the inhalationpassageway 126 to allow the aerosolized matter to pass from thedischarge passageway 120 into the inhalation passageway 126 withoutobstruction for delivery to a user through the mouthpiece aperture 128.

In some instances, including the example embodiment shown in FIGS. 3Aand 3B, the seal member 130 may be arranged or otherwise configuredrelative to the canister 110 to move in direct correlation with movementof the canister 110 from the initial position I, as shown in FIG. 3A, tothe discharge position D, shown in FIG. 3B. For example, as shown in theexample embodiment of FIGS. 3A and 3B, a seal assembly 129 may beprovided and may include a static nozzle block 132 (also referred toherein as a valve stem block) and the seal member 130. The nozzle block132 may receive the valve stem 114 of the canister 110 and may define aportion of the discharge passageway 120. The seal member 130 may engageor interface with the nozzle block 132 when the seal member 130 is inthe closed position C to isolate the discharge passageway 120 from theinhalation passageway 126. The seal member 130 may include a separate orintegral seal device 133 to interface with the nozzle block 132. In someinstances, the seal device 133 may be formed as an integral portion ofthe seal member 130 via a multi-shot injection process. In otherinstances, the seal device 133 may be a distinct feature of a unitaryseal member 130, such as a bead or a ridge that provides a sealing edgethat may engage the nozzle block 132 when the seal member 130 is in theclosed position C. In other instances, the nozzle block 132 may includea separate or integral seal device to interface with the seal member130. In such instances, the seal device may be formed as an integralportion of the nozzle block 132 via a multi-discharge passageway shotinjection process, or the seal device may be a distinct feature of aunitary nozzle block 132, such as a bead or a ridge that provides asealing edge that may be engaged by the seal member 130 in the closedposition C. As shown in the example embodiment of FIGS. 3A and 3B, theseal member 130 may be provide in a cup-like form which cups the nozzleblock 132 or a portion of the nozzle block 132 that includes thedischarge orifice 122. In other instances, the seal member 130 may takeon different forms such as, for example, a planar sealing element (e.g.,rotating flap), a ball seal or a movable gate structure.

A seal actuator structure 136 (e.g., push rod) coupled to or otherwiseprovided on the canister body 116 may be arranged to act on the sealmember 130 to transition the seal member 130 to the open position O, asshown in FIG. 3B. In this manner, moving the canister 110 to dischargethe aerosolized matter also results in displacing the seal member 130 toopen the discharge passageway 120. The seal member 130 of the exampleembodiment is configured such that it moves away from the nozzle block132 out of the discharge path emanating from the discharge orifice 122before the outlet valve member 112 releases material from the canister110 through the discharge passageway 120 so as to not obstruct the flowof aerosolized matter through the discharge orifice 122 into theinhalation passageway 126. In some instances, for example, the sealmember 130 will be entirely outside of a reference cylinder that isaligned with a central axis defined by the discharge orifice 122 andthat is tangent to an outlet of the discharge passageway 120. In someinstances, the seal member 130 will be entirely outside of a referencecone having an opening angle of 90° that is aligned with a central axisdefined by the discharge orifice 122 and that is tangent to an outlet ofthe discharge orifice 122.

In accordance with the example embodiment of FIGS. 3A and 3B, thedischarge orifice 122 and a portion of the discharge passageway 120(e.g., a sump portion) is provided in the nozzle block 132. According tothe example embodiment shown in FIGS. 3A and 3B, the nozzle block 132 issupported in a fixed manner within the base housing 104 and isconfigured to receive the discharge end of the valve stem 114 thatextends from the canister 110. In other instances, the nozzle block 132may be formed integrally with the base housing 104. In still otherinstances, the nozzle block 132 and the seal member 130 may be portionsof a unitary component having a living hinge or other joint to enablethe seal member 130 to move relative to the nozzle block 132.

The seal member 130 may be biased toward the closed position C to engagethe stem block 132 by a return spring 138 (e.g., torsional spring, coilspring, leaf spring) or other biasing element (e.g., resilient band,elastically deformable member). In this manner, the seal member 130 maybe held securely in the closed position C until acted upon incoordination with the movement of the canister 110 from the initialposition I (FIG. 3A) to the discharge position D (FIG. 3B). In someinstances, the return spring 138 may be captured with the aerosoldelivery unit 100 to be held captive within the unit 100 upon failure ofthe return spring 138 or dislodgement of the return spring 138 from itsintended installation position.

Although the seal member 130 and the stem block 132 are shown in theexample embodiment as two separate components that are connected by ahinge arrangement 134 to interface with each other to selectively sealthe discharge passageway 120, it is appreciated that various othersealing arrangements may be provided in lieu of the illustratedarrangement. For example, as described above, the stem block 132 and theseal member 130 may be portions of a unitary component having a livinghinge or other joint to enable the seal member 130 to move relative tothe nozzle block 132.

FIGS. 17 and 18 show another example embodiment of an aerosol deliveryunit 600 for selectively delivering a dose of aerosolized matter(referred to generally as a metered dose inhaler or MDI). The aerosoldelivery unit similarly includes a seal member 630 movable between aclosed position C (FIG. 17), in which the seal member 630 covers adischarge outlet of the discharge passageway 620, namely, dischargeorifice 622, in order to isolate the discharge passageway 620 from theinhalation passageway 626, and an open position O (not shown), in whichthe discharge outlet, namely, discharge orifice 622, is in fluidcommunication with the inhalation passageway 626 to allow theaerosolized matter to pass from the discharge passageway 620 into theinhalation passageway 626 without obstruction for delivery to a userthrough the mouthpiece aperture 628. According to the embodimentillustrated in FIGS. 17 and 18, at least a portion of the seal member630 may be biased toward the closed position C by a biasing element 638,such as, for example, a resilient band, which contacts a portion of theseal member 630 and urges it toward the closed position C throughoutoperation. One of ordinary skill in the relevant art will appreciatethat the biasing element 638 may deform elastically during actuation ofthe canister 610 and displacement of the seal member 630 to an openposition and that the magnitude of the biasing force may vary throughoutmovement of the seal member 630, increasing with the amount that thebiasing element 638 is displaced. As shown in the example embodiment ofFIGS. 17 and 18, the biasing element 638, may be provided in the form ofa resilient band that spans across and is in contact with or adjacent toa back side of the seal member 630.

With reference back to FIGS. 3A and 3B, the aerosol delivery unit 100further includes a desiccant chamber 150 containing a desiccant material152 that is in fluid communication with the discharge passageway 120 atleast when the aerosol delivery unit 100 is in a storage configurationand not actively discharging aerosolized matter. For example, inaccordance with the example embodiment shown in FIGS. 3A and 3B, thedesiccant chamber 150 is provided at an end of the canister 110 betweena lower end of the canister body 116 and a separate desiccant housing154 and stem seal 156 that are coupled to the end of the canister 110.The desiccant material 152 may be provided in disc form and may includea central aperture through which the valve stem 114 of the canister 110passes. The stem seal 156 may be an annular seal formed integrally withthe desiccant housing 154, such as, for example, via a multi-shotinjection molding process, or may otherwise be provided as a separateseal component coupled to the desiccant housing 154. In some instances,the stem seal 156 may be provided as a bellows type seal that is securedbetween the valve stem 114 and the desiccant housing to provide adesiccant chamber 150 having a volume that varies as the stem seal 156is deformed as the canister 110 is displaced during an inhalation event.In other instances, such as the example embodiment shown in FIGS. 3A and3B, the desiccant chamber 150 may have a fixed volume.

As can be appreciated from FIG. 3A, the desiccant material 152 withinthe desiccant chamber 150 is in fluid communication with the dischargepassageway 120 through the aperture 124 in the side of the valve stem114 that is otherwise used to pass the matter contained in the canisterbody 116 toward the discharge orifice 122 when the valve stem 114 isdisplaced during an inhalation event. In this manner, the dischargepassageway 120 remains exposed to the desiccant material 152 when thecanister 110 is in the initial position I, such as when storing the unit100. In some instances, the desiccant material may be sufficient to keepthe discharge passageway dry (e.g., <25% RH) between uses forsubstantially the entire product life of the canister of material to bedischarged.

Advantageously, the desiccant housing 154 may be coupled to the end orcollar of the canister 110 to form a cartridge 160 therewith that isreadily removable from the base housing 104. In this manner, thedesiccant housing 154 and canister 110 may be easily removed from thebase housing 104 to replace the canister 110 when depleted and/or toreplace the desiccant material 152 as desired. The desiccant housing 154may be coupled to the end or collar of the canister 110 via a resilientband, clips, detents or other fastening devices or techniques, includingfriction fit or interference fit arrangements. Although the desiccantchamber 150 is shown in the example embodiment of FIGS. 3A and 3B asbeing coupled to a lower end or collar of the canister 110, it isappreciated that in other embodiments a desiccant chamber may beprovided in a separate desiccant housing that is coupled to the basehousing 104 separate from the canister 110, the desiccant chamber may beformed integrally in the base housing itself, or the desiccant chambermay be provided in a separate component that is attached to the basehousing 104, such as a mouthpiece cap, as shown and described in greaterdetail elsewhere herein. In addition, the desiccant material may beprovided in a variety of different forms, such as gel form, powder form,granular form or molded form, and may consist of or comprise differentmaterials, such as silica, activated charcoal, calcium sulfate orcalcium chloride. Still further, it is appreciated that in someembodiments a desiccant chamber and the associated desiccant may beomitted altogether.

As previously described, the desiccant housing 154 may be coupled to theend or collar of the canister 110 to form a cartridge 160 that isinstallable in the base housing 104 to engage the stem block 132 andoperate in conjunction with the seal member 130 to provide some of thefunctionality described herein. Further details of the components of thecartridge 160, stem block 132 and seal member 130 are shown in FIGS. 3Cand 3D. As shown in FIGS. 3C and 3D, the desiccant housing 154 may forma cup-like structure with a generally cylindrical sidewall that is sizedand shaped to receive a lower end of the canister 110. The desiccantmaterial 152 may be provided in a molded form and may have a generallyannular shape. The desiccant material 152 may be positioned in a lowerend of the desiccant housing 154. The desiccant housing 154 may includeone or more locating or coupling features 155 to assist in joining orotherwise positioning the desiccant material 152 within the desiccanthousing 154. According to the example embodiment shown in FIGS. 3C and3D, the desiccant material 152 is shaped so as to not obstruct a valvestem aperture 157 (FIG. 3D) provided in the desiccant housing 154through which the valve stem 114 of the canister 110 is received. Moreparticularly, the valve stem aperture 157 is provided in stem seal 156,which may be formed integrally with the desiccant housing 154, such as,for example, via a multi-shot injection molding process, and thedesiccant material 152 has an annular form with a central aperture 153to provide the valve stem 114 of the canister 110 with unimpeded accessto the valve stem aperture 157 of the stem seal 156 of the desiccanthousing 154.

With continued reference to FIGS. 3C and 3D, a canister seal 117 may bepositioned around the canister body 116, such as around a lower neckportion thereof, to provide a resilient member between the canister body116 and the desiccant housing 154 which may be compressed when thecanister 110 and the desiccant housing 154 are coupled together. Thecanister seal 117 may provide a seal location to assist in isolating thedesiccant chamber 150 (FIGS. 3A and 3B) when the aerosol delivery unit100 is fully assembled and in preventing the ingress of moisture intosaid desiccant chamber 150 other than through the discharge passageway120. In a similar manner, the stem seal 156 may provide a seal locationto assist in isolating the desiccant chamber 150 (FIGS. 3A and 3B) whenthe aerosol delivery unit 100 is fully assembled and in preventing theingress of moisture into said desiccant chamber 150 other than throughthe discharge passageway 120. In this manner, the desiccant chamber 150is effectively isolated from the external environment apart from thedischarge passageway 120, which may be exposed to the externalenvironment when discharging medicament or, in the case of a unit inwhich the seal member 130 is omitted, when the inhalation passageway 120is otherwise exposed to the external environment, such as when themouthpiece cap 105 is removed from the base housing 104 of the aerosoldelivery unit 100.

With the canister 100 loaded in the desiccant housing 154, the valvestem 114 protrudes from a lower end thereof to be subsequently receivedin the nozzle block 132 provided in the base housing 104. The desiccanthousing 154 may further include a latch 159, detent mechanism or othercoupling arrangement for removably securing the cartridge 160 within thebase housing 104. For example, the desiccant housing 154 may include aresilient latch 159 that is configured to engage a latching aperture(not shown) in the base housing 104 to assist in retaining the cartridge160 within the base housing 104. The latch 159 may be depressed toselectively remove the cartridge 160 from the base housing 104 as neededor desired. Other features may be included in the desiccant housing 154and/or the base housing 104 to assist in locating the cartridge 160 inthe base housing 104 and in guiding the cartridge 160 relative to thebase housing 104 as it is depressed during use to actuate the valve stem114 and release a dose of material.

With continued reference to FIGS. 3C and 3D, the cartridge 160 mayinclude a seal actuator component 135 coupled to or integrated with alower end of the desiccant housing 154 to provide the seal actuatorstructure 136 (e.g., push rods) which acts on the seal member 130 duringuse to transition the seal member 130 to the open position O, as shownin FIG. 3B. The seal actuator component 135 may be removably coupled tothe lower end of the desiccant housing 154 and may be configured suchthat the seal actuator structure 136 extends through one or morecorresponding apertures 137 in the nozzle block 132 to assist in guidingand supporting the seal actuator structure 136 as it acts on the sealmember 130 to displace the seal member 130 during the inhalation event.For example, according to the illustrated embodiment in FIGS. 3 through3D, the seal actuator structure 136 comprises a pair of push rods thatextend through corresponding apertures 137 in the nozzle block 132 andare positioned to engage lugs 139 on the seal member 130 for driving theseal member 130 to the open position O as the canister 110 is depressed.In some instances, the push rods (or other seal actuator structure 136)are configured to move past the lugs 139 before reaching the end oftheir travel such that the push rods hold the seal member 130 open atthe end of their travel without imparting a downward force on the sealmember 130. Although the seal actuator structure 136 is shown anddescribed in the example embodiment as a pair of push rods, it isappreciated that other structures, including linkage arrangements, maybe provided to transform movement of the canister 110 when discharging adose of the material in the canister 110 to movement of the seal member130 to uncover the discharge passageway 120.

FIG. 4 shows another example embodiment of an aerosol delivery unit 200for selectively delivering a dose of aerosolized matter (referred togenerally as a metered dose inhaler or MDI). The aerosol delivery unit200 similarly includes a base housing 204 and a canister 210 received inthe base housing 204, the canister 210 being displaceable from aninitial position to a discharge position for selectively discharging adose of aerosolized matter for inhalation by a user. The canister 210comprises a canister body 216, which contains the matter to bedischarged, and an outlet valve member 212, which includes a movablevalve stem 214 that extends from the canister body 216. The valve stem214 defines a portion of a discharge passageway 220 extending from thecanister body 216 to a discharge orifice 222 that is provided within theaerosol delivery unit 200, which in turn leads to an inhalationpassageway 226 through which the aerosolized matter passes before beingdischarged through a mouthpiece aperture 228 for inhalation by the userduring an inhalation event.

With continued reference to FIG. 4, the aerosol delivery unit 200further includes a seal member 230 movable between a closed position(not shown), in which the seal member 230 covers a discharge outlet ofthe discharge passageway 220, namely, discharge orifice 222, in order toisolate the discharge passageway 220 from the inhalation passageway 226,and an open position O, as shown in FIG. 4, in which the dischargeoutlet, namely, discharge orifice 222, is in fluid communication withthe inhalation passageway 226 to allow the aerosolized matter to passfrom the discharge passageway 220 into the inhalation passageway 226without obstruction for delivery to a user through the mouthpieceaperture 228.

In some instances, including the example embodiment shown in FIG. 4, theaerosol delivery unit 200 may include a mouthpiece cap 260 and the sealmember 230 may be arranged or otherwise configured relative to themouthpiece cap 260 to move in coordination with movement of themouthpiece cap 260. For example, as shown in the example embodiment ofFIG. 4, the seal member 230 may be operatively coupled to a cam portion262 of the mouthpiece cap 260 such that the seal member 230 is movedaway from the closed position toward the open position O as themouthpiece cap 260 is rotated away from the end of the unit 200comprising the mouthpiece aperture 228. Conversely, as the mouthpiececap 260 is rotated back toward the end of the unit 200 comprising themouthpiece aperture 228, the seal member 230 may be displaced toward theclosed position to seal the discharge passageway 220. In this manner,the discharge orifice 222 may be uncovered as a user prepares to take adose of the aerosolized matter by removing the mouthpiece cap 260 androtating it away from the end of the unit 200 containing the mouthpieceaperture 228, and then covered again as the user replaces the mouthpiececap 260 to store the unit 200 for future use.

FIGS. 5 through 7 show a valve stem block 300 of another exampleembodiment of an aerosol delivery unit for selectively delivering a doseof aerosolized matter. The valve stem block 300 may be positioned withina base housing of the aerosol delivery unit and may be configured toreceive the valve stem of a conventional canister for a metered doseinhaler. FIGS. 5 and 6 show the valve stem block 300 in an exploded viewand a collapsed view, respectively, and FIG. 7 provides across-sectional side view thereof. As shown in FIGS. 5 through 7, a sealmember 330 is operatively coupled to a valve stem block housing 304 tomove between a closed position C, as shown in FIG. 6, and an openposition O, as shown in FIG. 7. A linkage 332 is operatively coupled tothe valve stem block housing 304 and the seal member 330 to assist inmoving the seal member 330 between the closed position C (FIG. 6) andthe open position O (FIG. 7). According to the example embodiment of thevalve stem block 300 of FIGS. 5 through 7, the seal member 330 isconfigured to rotate or flip up to uncover a discharge orifice 322formed in the valve stem block housing 304 in response to the canister(not shown) pressing upon a push member 334 extending from the stemblock housing 304 when the canister is depressed to a dischargeposition, the push member 334 in turn pressing upon the linkage 332 tocause the seal member 330 to rotate as the linkage 332 acts upon a cammember 331 of the seal member 330. When the canister returns to itsinitial position, a return spring 338 or other bias member urges thelinkage 332 to urge the seal member 330 back into the closed position C(FIG. 6). In this manner, the seal member 330 is held in a normallyclosed position C (FIG. 6) and moved to the open position O (FIG. 7)only when the canister is depressed to deliver a dose of the aerosolizedmatter.

Advantageously, the linkage 332 is arranged to convert or amplify arelatively small vertical displacement associated with a stroke of thecanister to a relatively large rotational movement of the seal member330. Furthermore, the linkage 332 is configured to move the seal member330 completely out of the flow path of the aerosolized matter before thematter is discharged through the discharge orifice 322 at the end of thedischarge passageway 320. In this manner, at least a portion of the sealmember 330 may move a distance greater than a travel distance of thestroke of the canister.

With continued reference to FIGS. 5 through 7, the valve stem blockhousing 304 of the valve stem block 300 may further include or define adesiccant chamber 350 containing a desiccant material (not shown) whichis in fluid communication with the discharge passageway 320 passingthrough the stem block housing 304. As such, the valve stem block 300may comprise a self-contained assembly sufficient to selectively isolatethe discharge passageway 320 and remove moisture therefrom when acanister is loaded therein and not actively discharging aerosolizedmatter. In some instances, the desiccant material may be sufficient tokeep the discharge passageway dry (e.g., <25% RH) between uses forsubstantially the entire product life of the canister of material to bedischarged. According to this embodiment, the desiccant material isexposed to a downstream end of the discharge passageway 320 rather thanan upstream end through the aperture in the side of the valve stem ofthe canister that is otherwise used to pass the matter contained in thecanister body toward the discharge orifice 322 when the valve stem isdisplaced during an inhalation event.

FIGS. 8 through 9B show a similar valve stem block 400 of anotherexample embodiment of an aerosol delivery unit for selectivelydelivering a dose of aerosolized matter. The valve stem block 400 may bepositioned within a base housing of the aerosol delivery unit and may beconfigured to receive the valve stem of a conventional canister for ametered dose inhaler. FIG. 8 provides a skewed isometric view of aportion of the valve stem block 400 and FIGS. 9A and 9B providecross-sectional side views of the valve stem block 400 with a sealmember 430 thereof in a closed position C and an open position O,respectively.

As shown in FIGS. 8 through 9B, the seal member 430 is operativelycoupled to a valve stem block housing 404 to move between the closedposition C, as shown in FIG. 9A, and the open position O, as shown inFIG. 9B. A linkage 432 is operatively coupled to the valve stem blockhousing 404 and the seal member 430 to assist in moving the seal member430 between the closed position C (FIG. 9A) and the open position (FIG.9B). According to the example embodiment of FIGS. 8 through 9B, the sealmember 430 is configured to rotate or flip up to uncover a dischargeorifice 422 (FIG. 8) formed in the valve stem block housing 404 inresponse to the canister (not shown) pressing upon a push member 434extending from the stem block housing 404 when the canister is depressedto a discharge position, the push member 334 in turn pressing upon thelinkage 432 to cause the seal member 430 to rotate as the linkage 432acts upon a cam member 431 of the seal member 430. When the canisterreturns to its initial position, a return spring (not visible) or otherbias member urges the linkage 432 to urge the seal member 430 back intothe closed position C (FIG. 9A). In this manner, the seal member 430 isheld in a normally closed position C (FIG. 9A) and moved to the openposition O (FIG. 9B) only when the canister is depressed to deliver adose of the aerosolized matter. As shown in FIG. 8, the dischargeorifice 422 may be encircled by a ridge 423 or other feature that mayinterface with the seal member 430 in the closed position C to assist increating and maintaining a seal that isolates the upstream dischargepassageway 420 from a downstream inhalation passageway (not shown).

The embodiments described above provide a few examples of various sealmember arrangements and desiccant chamber arrangements suitable forselectively isolating the discharge passageway of a metered dose inhaleror other drug delivery device and for removing moisture from saidisolated passageway. It is appreciated, however, that various other sealmember arrangements and desiccant chamber arrangements may be utilizedto provide the same or similar functionality.

For example, FIG. 10 provides schematic diagrams of various seal memberarrangements that may be used to selectively isolate a dischargepassageway of an aerosol delivery unit, including arrangements in whichthe seal member may pivot, slide or rotate between a closed position andan open position to cover the discharge orifice of the aerosol deliveryunit and isolate a discharge passageway thereof.

A desiccant chamber may also be provided in any suitable location andmanner to communicate with the isolated discharge passageway of theaerosol delivery unit. This may include a chamber formed or otherwisecoupled to the end of the canister, such as, for example, the embodimentshown in FIGS. 3A and 3B.

In other instances, a desiccant housing may be provided within the basehousing of the aerosol delivery unit and may be configured to remainwithin the base housing when the canister is removed therefrom, such asmay be the case when installing a replacement canister, or cleaning theunit. For instance, FIG. 11 illustrates one example embodiment of anaerosol delivery unit having a desiccant housing located in a basehousing of the aerosol delivery unit separate from the canister, whichis in fluid communication with the discharge passageway when the aerosoldelivery unit is not actively discharging medicament or other matter.FIG. 12 illustrates yet another example embodiment of an aerosoldelivery unit having a desiccant housing located in the base housing ofthe aerosol delivery unit separate from the canister. According to theembodiment of FIG. 12, the aerosol delivery unit further includes amovable gate arrangement for selectively isolating the desiccant chamberfrom the discharge passageway when the canister is removed from theunit. In this manner, the desiccant chamber may be sealed when thecanister is removed, such as may be the case when cleaning the aerosoldelivery unit.

In still other embodiments, the base housing itself may include adesiccant housing portion that defines the desiccant chamber. FIG. 13shows one example embodiment of an aerosol delivery unit having adesiccant chamber formed integrally with the housing thereof. In suchinstances, a supplemental seal member may be provided to seal theaperture in the side of the valve stem of the canister, which mayotherwise be exposed to the external environment when the canister is inits initial position. An example of such a supplemental seal is shown inFIG. 14 encircling a base of the valve stem adjacent the canister body.

In still yet other embodiments, desiccant material may be providedwithin other components of the host aerosol delivery unit, including,for example, within a mouthpiece cap used to cover the mouthpieceaperture of the aerosol delivery unit when not in use. For example, FIG.15 shows one example embodiment of an aerosol delivery unit 500, whichincludes a mouthpiece cap 505 for covering a mouthpiece 504 of theaerosol delivery unit 500 having a mouthpiece aperture 528 that is influid communication with an inhalation passageway 526 through whichaerosolized matter is discharged during operation of the aerosoldelivery unit 500. A desiccant chamber 550 containing a desiccantmaterial (not shown) is provided within the mouthpiece cap 505, and themouthpiece cap 505 includes a seal member 530 (shown in a non-deformedstate), such as a split seal valve, an umbrella valve or other sealvalve, which is configured to close upon removal of the mouthpiece cap505 from a mouthpiece 504 of the aerosol delivery unit 500 in order toisolate the desiccant material in the desiccant chamber 550 from theexternal environment when the mouthpiece cap 505 is removed. The sealmember 530 is arranged within the mouthpiece cap 505 and a protrusion531 is provided within the inhalation passageway 526 to displace theseal member 530 to bring the desiccant chamber 550 into fluidcommunication with a discharge orifice 522 and a discharge passageway520 of the unit 500 located upstream of the inhalation passageway 526when the mouthpiece cap 505 is installed over the mouthpiece 504 toprevent access to the inhalation passageway 526. In this manner, whenthe mouthpiece cap 505 is secured over the mouthpiece 504, the dischargeorifice 522 and discharge passageway 520 are isolated from theinhalation passageway 526 and the external environment while also beingexposed to desiccant within the desiccant chamber 550. Conversely, whenthe mouthpiece cap 505 is removed, the discharge passageway 520 anddischarge orifice 522 are brought into fluid communication with theinhalation passageway 526.

In order to prevent loss of the mouthpiece cap 505 and help ensure thatit will be replaced on the mouthpiece 504 after a user receives a doseor doses of the aerosolized matter, the mouthpiece cap 505 may betethered to a housing 560 of the aerosol delivery unit 500 by a tethermember 562 connected to the housing 560 via a living hinge 564 or otherconnection. In addition, the mouthpiece cap 505 may be connected to thetether member 562 by a sliding joint 566 that enables the mouthpiece cap505 to be withdrawn from the mouthpiece 504 before the mouthpiece cap505 is rotated away from the end of the unit 500 containing themouthpiece aperture 528.

Although the seal member 530 shown in the example embodiment of FIG. 15is shown as a deformable membrane (e.g., split seal valve), it isappreciated that a variety of other types of seal arrangements may beused in lieu thereof (e.g., umbrella valve or other valve that isconfigured to close upon removing the mouthpiece cap and to open whenthe mouthpiece cap is installed). For example, with reference to FIG.16, a mouthpiece cap may be provided with a seal member comprising aspring-biased plunger element that is actuated in a direction opposite abias applied by a spring thereof when the mouthpiece cap closes themouthpiece aperture to thereby expose the discharge passageway to thedesiccant material.

It is further appreciated that embodiments disclosed herein may beprovided in the form of a manually actuatable inhaler (also referred toas a press-and-breathe inhaler) or a breath actuated inhaler, includingmechanical power actuated inhalers and electrical power (i.e.,electromechanical) actuated inhalers. Accordingly, in some embodiments,the aerosol delivery units described herein may further include, amongother things, a power source (mechanical or electrical) and an actuatorcoupled to the power source for moving the canister from the initialposition to the discharge position to deliver the dose of aerosolizedmatter, such as in response to a user inhaling on the aerosol deliveryunit or other trigger event. Moreover, in some embodiments, movement ofthe seal members disclosed herein may be electronically controlled andcoordinated with movement of the canister. Still further, it isappreciated that aspects and features of the embodiments disclosedherein may be incorporated in or adapted for use with a dry powderinhaler (DPI) apparatus or a variety of other drug delivery apparatuseshaving a drug delivery tract.

It will also be appreciated that in view of the present disclosurerelated methods of making and operating a drug delivery apparatus may beprovided. For example, one example embodiment of a method of controllingthe environment within a drug delivery tract of a drug deliveryapparatus may be summarized as including: discharging a dose of a drugthrough the drug delivery tract; isolating at least a portion of thedrug delivery tract to form an isolated environment within the drugdelivery apparatus; and desiccating the isolated environment to reducewater vapor content therein. The method may further include unsealingthe at least a portion of the drug delivery tract; and discharging asubsequent dose of the drug through the drug delivery tract, whereinunsealing the at least a portion of the drug delivery tract iscoordinated with actuation of the aerosol canister such that thedelivery tract is completely unobstructed as the drug formulation passesthrough the drug delivery tract. Discharging the dose of the drug mayinclude discharging a moisture sensitive formulation through the drugdelivery tract, and desiccating the isolated environment maysubstantially prevent the accumulation of drug residue within the atleast a portion of the drug delivery tract throughout operation of thedrug delivery apparatus. In some instances, discharging the dose of thedrug may include discharging the drug formulation through a dischargevalve of an aerosol canister into the drug delivery tract, and isolatingthe at least a portion of the drug delivery tract may include sealingthe at least a portion of the drug delivery tract at or downstream of adischarge orifice through which the drug formulation is dispersed afterbeing discharged through the discharge valve of the aerosol canister.

As another example, an embodiment of operating a drug delivery apparatusin the form of an aerosol delivery unit may be summarized as including:discharging at least one dose of aerosolized matter through aninhalation passageway that is in fluid communication with a dischargepassageway extending from an outlet of an aerosol canister dischargevalve toward the inhalation passageway, and thereafter, sealing thedischarge passageway to isolate the discharge passageway from theinhalation passageway and an environment external to the aerosoldelivery unit. The method may further include temporarily storing theaerosol delivery unit with the discharge passageway isolated from theinhalation passageway, and, prior to discharging at least one other doseof aerosolized matter through the inhalation passageway, unsealing thedischarge passageway such that the discharge passageway and theinhalation passageway are in fluid communication. The method may furtherinclude exposing the discharge passageway to a desiccant material atleast while temporarily storing the aerosol delivery unit.

Although embodiments are shown and described herein largely in thecontext of aerosol delivery units that are well adapted to bothtemporarily seal the discharge passageway and to expose the dischargepassageway to a desiccant material, it is appreciated that someembodiments may include only some of this functionality, namely,exposing the discharge passageway to a desiccant material withoutsealing the passageway off from the adjacent and downstream inhalationpassageway, or selectively sealing off the discharge passageway withoutexposing the sealed passageway to a desiccant material. Regarding theformer, the desiccant material may be positioned to be in fluidcommunication with the discharge passageway through the aperture in theside of the valve stem of the canister, through the discharge orifice,through a passageway in a valve stem block, or a combination thereof,without providing a seal arrangement to seal off the dischargepassageway.

For example, the desiccant arrangement shown in FIGS. 3A and 3B may beemployed without the displaceable seal member 130. For instance, FIGS.19 through 21B show another example embodiment of an aerosol deliveryunit 700 for selectively delivering a dose of aerosolized matter(referred to generally as a metered dose inhaler or MDI), which includesstructures and associated functionality for exposing the dischargepassageway to a desiccant material without having a seal member forsealing the discharge passageway off from the adjacent and downstreaminhalation passageway.

With reference to FIGS. 19 through 21B, the aerosol delivery unit 700includes a base housing 704 and a canister 710 received in the basehousing 704, the canister 710 being displaceable from an initialposition I, as shown in FIG. 21A, to a discharge position D, as shown inFIG. 21B, for selectively discharging a dose of aerosolized matter forinhalation by a user. The canister 710 comprises a canister body 716,which contains the matter to be discharged, and an outlet valve member712, which includes a movable valve stem 714 that extends from thecanister body 716. The valve stem 714 defines a portion of a dischargepassageway 720 extending from the canister body 716 to a dischargeorifice 722 provided within the aerosol delivery unit 700, which in turnleads to an inhalation passageway 726 through which the aerosolizedmatter passes before being discharged through a mouthpiece aperture 728for inhalation by the user during an inhalation event. The dischargepassageway 720 and the inhalation passageway 726 may be collectivelyreferred to as a drug delivery tract. As will be appreciated by those ofordinary skill in the relevant art, when the valve stem 714 is displacedrelative to the canister body 716, as shown in FIG. 21B, a metered doseof the matter contained with the canister body 716 will be dischargedthrough the discharge orifice 722 for inhalation by a user via theinhalation passageway 726.

With reference to FIG. 19, the aerosol delivery unit 700 may furtherinclude a dose counter assembly 707 secured to an upper under of thecanister 710 to provide dose counting functionality and to provide auser interface for depressing the canister 710. The aerosol deliveryunit 700 may also include a cap 705 to cover the mouthpiece aperture 728of the aerosol delivery unit 700 when storing the unit 700. The cap 705may be completely separable from the base housing 704, or may be coupledto the base housing 704 by a tether 706, which enables the cover 705 tobe removed from the mouthpiece aperture 728 while still remainingcoupled to the base housing 704.

With reference to FIGS. 21A and 21B, the aerosol delivery unit 700further includes a desiccant chamber 750 containing a desiccant material752 that is in fluid communication with the discharge passageway 720 atleast when the aerosol delivery unit 700 is in a storage configurationand not actively discharging aerosolized matter. For example, inaccordance with the example embodiment shown in FIGS. 21A and 21B, thedesiccant chamber 750 is provided at an end of the canister 710 betweena lower end of the canister body 716 and a separate desiccant housing754 and stem seal 756 that are coupled to the end of the canister 710.The desiccant material 752 may be provided in a semi-annular form (asshown in FIG. 20) and may include a central passage 753 through whichthe valve stem 714 of the canister 710 extends. The stem seal 756 may bean annular seal formed integrally with the desiccant housing 754, suchas, for example, via a multi-shot injection molding process, or mayotherwise be provided as a separate seal component coupled to thedesiccant housing 754. In some instances, the stem seal 756 may beprovided as a bellows type seal that is secured between the valve stem714 and the desiccant housing 754 to provide a desiccant chamber 750having a volume that varies as the stem seal 756 is deformed as thecanister 710 is displaced during an inhalation event. In otherinstances, such as the example embodiment shown in FIGS. 21A and 21B,the desiccant chamber 750 may have a fixed volume.

As can be appreciated from FIG. 21A, the desiccant material 752 withinthe desiccant chamber 750 is in fluid communication with the dischargepassageway 720 through an aperture 724 in the side of the valve stem 714that is otherwise used to pass the matter contained in the canister body716 toward the discharge orifice 722 when the valve stem 714 isdisplaced during an inhalation event. In this manner, the dischargepassageway 720 remains exposed to the desiccant material 752 when thecanister 710 is in the initial position I, such as when storing the unit700. In some instances, the desiccant material may be sufficient to keepthe discharge passageway dry (e.g., <25% RH) between uses forsubstantially the entire product life of the canister of material to bedischarged.

Advantageously, the desiccant housing 754 may be coupled to the end orcollar of the canister 710 to form a cartridge 760 (FIG. 20) that isreadily removable from the base housing 704. In this manner, thedesiccant housing 754 and canister 710 may be easily removed from thebase housing 704 to replace the canister 710 when depleted and/or toreplace the desiccant material 752 as desired. The desiccant housing 754may be coupled to the end or collar of the canister 710 via a resilientband, clips, detents or other fastening devices or techniques, includingfriction fit or interference fit arrangements. Although the desiccantchamber 750 is shown in the example embodiment of FIGS. 21A and 21B asbeing coupled to a lower end or collar of the canister 710, it isappreciated that in other embodiments a desiccant chamber may beprovided in a separate desiccant housing that is coupled to the basehousing 704 separate from the canister 710, the desiccant chamber may beformed integrally in the base housing itself, or the desiccant chambermay be provided in a separate component that is attached to the basehousing 704. In addition, the desiccant material may be provided in avariety of different forms, such as gel form, powder form, granular formor molded form, and may consist of or comprise different materials, suchas silica, activated charcoal, calcium sulfate or calcium chloride.

According to the example embodiment of FIGS. 19 through 21B, thedesiccant housing 754 may be coupled to the end or collar of thecanister 710 to form a cartridge 760 that is installable in the basehousing 704 to engage a stem block 732 provided therein. Further detailsof the components of the cartridge 160 and the stem block 732 can beseen in the exploded view of FIG. 20. As shown in FIG. 20, the desiccanthousing 754 may form a cup-like structure with a generally cylindricalsidewall that is sized and shaped to receive a lower end of the canister710. The desiccant material 752 may be provided in a molded form. Thedesiccant material 752 may be configured to be positioned in a lower endof the desiccant housing 754. The desiccant housing 754 may include oneor more locating or coupling features to assist in joining or otherwisepositioning the desiccant material 752 within the desiccant housing 754.The desiccant material 752 may be shaped so as to not obstruct a valvestem aperture of the stem seal 756 provided in the desiccant housing 754for receiving the valve stem 714 of the canister 710. For example, thedesiccant material 752 may have a semi-annular shape with a centralpassage 753 or other clearance for the valve stem 714. In someinstances, such as in the example embodiment shown in FIGS. 19 through21B, the desiccant material 752 may be shaped to partially encircle thevalve stem 714 and may extend beyond a terminal end of the valve stem714. The desiccant housing 754 and the desiccant material 752 may alsobe correspondingly shaped, and may each extend beyond a terminal end ofthe valve stem 714. In this manner, the desiccant material 752 maysubstantially fill the desiccant chamber 750 and provide a relativelylarge volume of desiccant material suitable to continuously removemoisture at least from the passage of the valve stem 714 throughout theusable life of the material (e.g., drug formulation) contained in thecanister 710.

With reference to FIGS. 21A and 21B, a canister seal 717 may bepositioned around the canister body 716, such as around a lower neckportion thereof, to provide a resilient member between the canister body716 and the desiccant housing 754 which may be compressed when thecanister 710 and the desiccant housing 754 are coupled together. Thecanister seal 717 may provide a seal location to assist in isolating thedesiccant chamber 750 when the aerosol delivery unit 700 is fullyassembled and in preventing the ingress of moisture into said desiccantchamber 750 other than through the discharge passageway 720. In asimilar manner, the stem seal 756 may provide a seal location to assistin isolating the desiccant chamber 750 when the aerosol delivery unit700 is fully assembled and in preventing the ingress of moisture intosaid desiccant chamber 750. In this manner, the desiccant chamber 750 iseffectively isolated from the external environment apart from thedischarge passageway 720, which may be exposed to the externalenvironment through the inhalation passageway 726 when the mouthpiececap 705 is removed from the base housing 704.

As can be appreciated from a review of FIGS. 21A and 21B, when the valvestem 714 is in an expanded position, the portion of the dischargepassageway 720 defined by the valve stem 714 is in fluid communicationwith the desiccant chamber 752 via the aperture 724 in the side of thevalve stem 714. Conversely, when the valve stem 714 of the canister 710is fully depressed, the desiccant chamber 752 is temporarily isolatedfrom the discharge passageway 720 defined by the valve stem 714.

Again, with the canister 700 loaded in the desiccant housing 754, thevalve stem 714 protrudes from a lower end thereof to be subsequentlyreceived in the nozzle block 732 provided in the base housing 704.According to the example embodiment of FIG. 20, the nozzle block 732 maybe provided in a mouthpiece unit 731 that is coupleable to the basehousing 704 and includes the inhalation passageway 726 and themouthpiece aperture 728 for delivering aerosolized matter to the user.As illustrated, when the cartridge 760 is installed, the desiccantmaterial 752 may extend from a location above the discharge orifice 722of the nozzle block 732 to a location below the discharge orifice 722,and may substantially fill the desiccant chamber 750 within thedesiccant housing 754 to provide a relatively large volume of desiccantmaterial suitable to continuously remove moisture at least from thepassage of the valve stem 714 throughout the usable life of the material(e.g., drug formulation) contained in the canister 710. In this manner,embodiments may be particularly well suited to eliminate, reduce orminimize the presence of moisture in the discharge passageway 720 and toeliminate, reduce or minimize any fouling associated therewith even whennot completely isolating the discharge passageway 720 from the externalenvironment after discharging the material during the inhalation event.

Moreover, aspects and features of the various embodiments describedabove may be combined to provide yet further embodiments. U.S.Provisional Patent Application No. 62/569,901, filed Oct. 9, 2017 andU.S. Provisional Patent Application No. 62/639,911, filed Mar. 7, 2018,to which the present application claims priority, are herebyincorporated herein by reference in their entirety. Aspects of theembodiments can be modified, if necessary to employ concepts of theapplications to provide yet further embodiments. These and other changescan be made to the embodiments in light of the above-detaileddescription. In general, in the following claims, the terms used shouldnot be construed to limit the claims to the specific embodimentsdisclosed in the specification and the claims, but should be construedto include all possible embodiments along with the full scope ofequivalents to which such claims are entitled.

1. A drug delivery device comprising: a canister containing a drugformulation and having a discharge valve and a valve stem defining avalve stem passage through which the drug formulation is selectivelydischarged; a desiccant housing attached to the canister with the valvestem extending through the desiccant housing; and a desiccant materialprovided in the desiccant housing in fluid communication with the valvestem passage.
 2. The drug delivery device of claim 1, furthercomprising: a base housing including an inhalation passageway throughwhich the drug formulation is discharged during an inhalation event; anda valve stem block including a discharge orifice in fluid communicationwith the inhalation passageway from which the drug formulation isejected during the inhalation event after passing through the valve stempassage, and wherein the canister, the desiccant housing and thedesiccant material form a cartridge that is removably installable in thebase housing with the valve stem of the canister engaging the valve stemblock when the cartridge is installed.
 3. The drug delivery device ofclaim 2 wherein, when the cartridge is installed, the desiccant materialextends from a location above the discharge orifice of the valve stemblock to a location below the discharge orifice.
 4. The drug deliverydevice of claim 1 wherein the valve stem of the canister includes anaperture in a side thereof, and wherein, when the valve stem is in anexpanded position, the valve stem passage is in fluid communication withthe desiccant material via the aperture in the side of the valve stem.5. The drug delivery device of claim 1 wherein the canister is removablyinstallable in the desiccant housing and a canister seal is positionedbetween the desiccant housing and the canister to assist in at leastpartially isolating the desiccant material from an external environmentof the drug delivery device.
 6. The drug delivery device of claim 1wherein the desiccant housing includes a stem seal formed integrallytherewith through which the valve stem extends, the stem seal assistingin at least partially isolating the desiccant material from an externalenvironment of the drug delivery device.
 7. The drug delivery device ofclaim 1 wherein the desiccant material is an annular or semi-annularmolded component.
 8. The drug delivery device of claim 1 wherein thedesiccant material is a semi-annular molded component, which partiallyencircles the valve stem and extends beyond a terminal end of the valvestem.
 9. The drug delivery device of claim 1 wherein the desiccanthousing and the desiccant material are correspondingly shaped, andwherein each of the desiccant housing and the desiccant material extendbeyond a terminal end of the valve stem.
 10. The drug delivery device ofclaim 1 wherein, apart from when the valve stem is depressed, thedesiccant material is arranged to continuously remove moisture at leastfrom the valve stem passage defined by the valve stem throughout theusable life of the drug formulation contained in the canister.
 11. Thedrug delivery device of claim 1 wherein, when the valve stem of thecanister is fully depressed, the desiccant material is isolated from thevalve stem passage and an external environment of the drug deliverydevice.
 12. The drug delivery device of claim 1, further comprising: abase housing including an inhalation passageway through which the drugformulation is discharged during an inhalation event; a mouthpieceaperture in fluid communication with the inhalation passageway throughwhich the aerosolized matter is discharged during an inhalation event;and a desiccant chamber within the desiccant housing in which thedesiccant material is contained, the desiccant chamber being in fluidcommunication with the discharge passageway at least when the aerosoldelivery unit is in a storage configuration.
 13. The drug deliverydevice of claim 12, wherein the desiccant housing and the canistercollectively define the desiccant chamber within which the desiccantmaterial is contained.
 14. The drug delivery device of claim 12, furthercomprising: a seal member movable between a closed position, in whichthe seal member covers a discharge outlet of the discharge passageway toisolate the discharge passageway from the inhalation passageway, and anopen position, in which the discharge outlet is in fluid communicationwith the inhalation passageway to allow the aerosolized matter to passfrom the discharge passageway into the inhalation passageway fordelivery to a user through the mouthpiece aperture.
 15. The drugdelivery device of claim 1, which is a metered dose inhaler.
 16. Thedrug delivery device of claim 15, wherein the drug formulation comprisesa medicament in bronchodilation therapy.
 17. The drug delivery device ofclaim 2, which is a metered dose inhaler.
 18. The drug delivery deviceof claim 17, wherein the drug formulation comprises a medicament inbronchodilation therapy.
 19. The drug delivery device of claim 12, whichis a metered dose inhaler.
 20. The drug delivery device of claim 19,wherein the drug formulation comprises a medicament in bronchodilationtherapy.